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【新文速递】2023年12月20日固体力学SCI期刊最新文章

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今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 1 篇,Mechanics of Materials 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 1 篇

International Journal of Solids and Structures

Visual investigation of static contact conditions at bolted joints

Guan-Sian Li, Yum Ji Chan

doi:10.1016/j.ijsolstr.2023.112621

螺栓连接处静态接触条件的目测调查

Accurate numerical models of physical systems are vital in engineering applications, and those for single components are generally accurate. However, there are significant errors in modelling the dynamics of bolted joints, which is a key source of friction in real-life systems, because existing experimental techniques are still far from offering sufficient understanding of the contact conditions of bolted joints. In the current study, static contact conditions of bolted joints are investigated with at least one component in the assembly being transparent. A novel visual identification method is proposed to (i) measure the clearance between plates in the vicinity of bolted joints and (ii) identify the contact conditions in receding contacts by applying a paste (known as Engineer’s blue) to the contact surface. The paste is thinner than most media applied in previous studies. Clearance results obtained by visual inspection are checked against micrometer profile tracing, and the contact regions predicted by the method are used to validate simulation results obtained from two contact mechanics algorithms. Difference between simulation and experiment is as low as 9% in terms of contact region diameters. Last but not least, the reproducibility of the method has been demonstrated, especially if the clearance is in the range of 2 to 5 μm.

精确的物理系统数值模型在工程应用中至关重要,单个组件的数值模型一般都很精确。然而,由于现有的实验技术还远未充分了解螺栓连接的接触条件,因此在模拟实际系统中摩擦的主要来源--螺栓连接的动态时,存在很大的误差。在当前的研究中,我们研究了螺栓连接的静态接触条件,其中至少有一个组件是透明的。研究提出了一种新颖的视觉识别方法:(i) 测量螺栓连接处附近板间的间隙;(ii) 通过在接触面上涂抹浆糊(称为工程师蓝)来识别后退接触中的接触状况。这种浆糊比以往研究中使用的大多数介质都要稀。通过目视检查获得的间隙结果与千分尺轮廓跟踪结果进行核对,该方法预测的接触区域用于验证两种接触力学算法获得的模拟结果。就接触区域直径而言,模拟和实验之间的差异低至 9%。最后但并非最不重要的一点是,该方法的可重复性得到了证明,尤其是当间隙在 2 至 5 μm 范围内时。


Journal of the Mechanics and Physics of Solids

Initiation of motility on a compliant substrate

Jocelyn Étienne, Pierre Recho

doi:10.1016/j.jmps.2023.105526

在顺应性基质上启动运动

The conditions under which biological cells switch from a static to a motile state are fundamental to the understanding of many healthy and pathological processes. In this paper, we consider a cell constrained to move along a one-dimensional track. We show that even in the presence of a fully symmetric protrusive activity at the cell edges, such a spontaneous transition can result from a feedback of the deformation of an elastic substrate on the cell traction forces. The loss of symmetry of the traction forces leading to the cell propulsion is rooted in the fact that the surface loading follows the substrate deformation, leading the cell to surf its own wake. The bifurcation between the static and motile states is characterized analytically and, considering the measurements performed on two cell types, we show that such an instability can realistically occur on soft in vivo substrates.

生物细胞从静止状态转为运动状态的条件是了解许多健康和病理过程的基础。在本文中,我们考虑了细胞受限沿一维轨道运动的情况。我们的研究表明,即使细胞边缘存在完全对称的突起活动,弹性基质的变形对细胞牵引力的反馈也会导致这种自发转换。导致细胞推进的牵引力失去对称性的根本原因在于,表面载荷随基底变形而变化,从而导致细胞自行冲浪。我们对静态和运动状态之间的分叉进行了分析,并通过对两种细胞类型的测量结果表明,这种不稳定性可能真实地发生在柔软的活体基底上。


Mechanics of Materials

Mechanical behaviour of ductile polymer cellular model structures manufactured by FDM

Jacopo Agnelli, Claudia Pagano, Irene Fassi, Laura Treccani, Fabio Bignotti, Francesco Baldi

doi:10.1016/j.mechmat.2023.104882

用 FDM 制造的韧性聚合物蜂窝模型结构的力学性能

In this work, Acrylonitrile-Butadiene-Styrene model structures were manufactured by FDM, and their mechanical behaviour investigated under compression, both at small and at large strains. The structure design strategy adopted, based on the use of circular cross-section beam-like elements formed under controlled conditions, led to obtain open-celled structures (with a porosity degree of ≈65%) composed of unit cells with different shapes and dimensions assembled to form regularly repeating patterns. The stress–strain behaviour, from cube- and prism-shaped specimens with different sizes and loaded along different directions, was discussed in the light of the outcomes from (i) cyclic compression experiments and (ii) morphological analyses of cryogenic fracture surfaces of specimens compressed at high strain levels. The response along the 3D-stacking direction was traced back to the elastic–plastic case, with non-recoverable strain starting to accumulate between 3% and 5% strain and structure densification starting below 20%. The specimen size effects turned out to be little pronounced. Slightly higher levels of stiffness and strength were measured for the largest cube. This result was discussed on the basis of the peculiar morphology of the structure examined.

在这项工作中,通过 FDM 制造了丙烯腈-丁二烯-苯乙烯模型结构,并研究了其在小应变和大应变压缩条件下的机械性能。所采用的结构设计策略基于使用在受控条件下形成的圆形截面梁状元件,从而获得了开孔结构(孔隙度约为65%),由不同形状和尺寸的单元格组成,并组合成有规律的重复图案。根据(i)循环压缩实验和(ii)高应变水平压缩试样低温断裂表面形态分析的结果,讨论了不同尺寸和沿不同方向加载的立方体和棱柱形试样的应力应变行为。沿三维堆叠方向的响应可追溯到弹塑性情况,不可恢复应变在 3% 至 5% 应变之间开始累积,结构致密化在 20% 以下开始。试样尺寸的影响并不明显。最大立方体的刚度和强度水平略高。对这一结果的讨论是基于所研究结构的特殊形态。


International Journal of Plasticity

Creep-fatigue life prediction of notched structure after an advanced surface strengthening treatment in a nickel-based superalloy at 650°C

Kai-Shang Li, Shu-Lei Yao, Lv-Yi Cheng, Run-Zi Wang, Li Sun, Hang-Hang Gu, Ji Wang, Ti-Wen Lu, Cheng-Cheng Zhang, Xian-Cheng Zhang, Shan-Tung Tu

doi:10.1016/j.ijplas.2023.103861

镍基超合金在 650°C 高温下经过高级表面强化处理后缺口结构的蠕变疲劳寿命预测

The elucidation of creep-fatigue damage mechanisms is still controversial for high-temperature structures after surface strengthening treatments, which serves as a critical foundation for the development of an accurate life prediction method. In this work, a numerical procedure is constructed for the prediction of creep-fatigue life improvement, where a dual-scale modeling approach is proposed to integrate important strengthening factors and microstructure features. The macro-scale finite element (FE) simulation aims to investigate the cyclic deformation behavior in a notched structure by using a viscoplastic constitutive model. The initial stress field is predetermined based on the experimental residual stress. The micro-scale FE analysis is employed to investigate the local damage evolution occurring at the notched root by combining size-dependent crystal plasticity with grain boundary cavity model. The cycle-by-cycle deformation histories are extracted from the macro-scale FE model and subsequently are utilized as boundary conditions in the micro-scale FE one. From the experimental perspective, the submerged micro-abrasive waterjet peening (SMA-WJP) process is carried out for creep-fatigue life improvement of the notched structure. Results shows that the notched structure treated by the SMA-WJP process forms an obvious plastic layer with the depth of 20 μm and residual stress with the maximum value of -926 MPa. The predicted numbers of cycles to crack initiation agree with the creep-fatigue experimental ones before and after SMA-WJP. In detail, the surface residual stress and plastic layer are unable to suppress the cavity nucleation on the grain boundaries of internal material. As a consequence, the creep-fatigue life improvement is diminished as the hold time increases, which can be accurately predicted by the developed numerical procedure.

对于表面强化处理后的高温结构,蠕变疲劳损伤机理的阐明仍存在争议,这也是开发精确寿命预测方法的重要基础。本研究构建了蠕变疲劳寿命提高预测的数值程序,提出了一种双尺度建模方法,以整合重要的强化因素和微观结构特征。宏观尺度的有限元(FE)模拟旨在利用粘塑性组成模型研究缺口结构的循环变形行为。初始应力场是根据实验残余应力预先确定的。采用微尺度有限元分析,结合尺寸相关晶体塑性和晶界空腔模型,研究缺口根部发生的局部损伤演变。从宏观尺度 FE 模型中提取逐周期变形历史,然后将其作为微观尺度 FE 模型的边界条件。从实验角度来看,采用浸没式微磨料水刀强化(SMA-WJP)工艺来提高缺口结构的蠕变疲劳寿命。结果表明,经 SMA-WJP 工艺处理的缺口结构形成了深度为 20 μm 的明显塑性层,残余应力的最大值为 -926 MPa。预测的裂纹萌发循环次数与 SMA-WJP 前后的蠕变疲劳实验次数一致。具体来说,表面残余应力和塑性层无法抑制内部材料晶界上的空洞成核。因此,随着保持时间的增加,蠕变疲劳寿命的提高幅度会减小,这一点可以通过所开发的数值程序准确预测。


Thin-Walled Structures

Laser beam oscillation welding for fatigue properties enhancement of tailor-welded blanks

Hana ŠEBESTOVÁ, Michal JAMBOR, Petr HORNÍK, Jan NOVOTNÝ, Libor MRŇA

doi:10.1016/j.tws.2023.111506

激光束振荡焊接用于提高定制焊接坯料的疲劳性能

Dissimilar thickness laser welded tailored blanks of two low-alloyed carbon steel grades were fabricated. Laser welds made without beam oscillation exhibited serious root undercuts. Although these notches did not degrade the tensile strength, they were detrimental to the fatigue lifetime of a weld joint. Therefore, laser welds with three different beam oscillation modes to modify the root were examined. Application of beam oscillation improved fatigue properties in all tested cases. The best results were achieved with line oscillation, even though this mode did not suppress weld root notches, suggesting other factors, besides joint geometry, contributing to the resulting fatigue properties.

用两种低合金碳钢制造了厚度不同的激光焊接定制坯件。在没有光束振荡的情况下进行的激光焊接会出现严重的根部缺口。虽然这些缺口不会降低抗拉强度,但对焊点的疲劳寿命不利。因此,我们研究了采用三种不同的光束振荡模式来改变根部的激光焊接。在所有测试案例中,光束振荡都改善了疲劳性能。直线振荡的效果最好,尽管这种模式并不能抑制焊缝根部的缺口,这表明除了焊点几何形状之外,还有其他因素也会影响所产生的疲劳性能。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemDeform疲劳断裂UG焊接裂纹材料螺栓
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首次发布时间:2024-11-05
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【新文速递】2023年12月9日固体力学SCI期刊最新文章

今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 3 篇International Journal of Solids and StructuresInfluence of crystal orientations on the creep fracture of a nickel-based single crystal superalloyChengjiang Zhang, Ping Wang, Yajie Deng, Xiaoshuai Wang, Zhixun Wen, Yeda Lian, Pengfei Hedoi:10.1016/j.ijsolstr.2023.112614晶体取向对镍基单晶超级合金蠕变断裂的影响Due to the anisotropy of the modulus of face-centered cubic cells, the nickel-based single crystal alloys exhibits substantial anisotropy at high temperatures. Their creep properties, especially the creep rupture lives, are related to the actuation of the slip system and the magnitude of the shear stress on the slip plane. The creep orientation sensitivity has been analyzed through creep experiments, as well as the microstructure and morphology of the fracture. On the macroscale, the necking sections of [001], [011] and [111] orientations are circular, elliptical and circular, respectively. Meanwhile, on the microscopic scale, the damage evolution caused by the expansion of the internal micropores in the single crystal alloy under the three orientations shows fourfold symmetry, double symmetry and triple symmetry, respectively. Based on the crystal plasticity theory, an anisotropic creep constitutive model and damage model are established to reflect the difference in creep deformation and damage evolution caused by orientation. The numerical simulations of the whole creep process of a second generation nickel-based single crystal superalloy show that the creep constitutive model and damage model can simulate the deformation and damage of the specimen under different orientations, and the creep life can be obtained.由于面心立方晶胞模量的各向异性,镍基单晶合金在高温下表现出很大的各向异性。它们的蠕变特性,尤其是蠕变断裂寿命,与滑移系统的驱动和滑移面上的剪应力大小有关。通过蠕变实验分析了蠕变取向敏感性以及断口的微观结构和形态。在宏观尺度上,[001]、[011]和[111]取向的缩颈截面分别为圆形、椭圆形和圆形。同时,在微观尺度上,三种取向下单晶合金内部微孔扩张导致的损伤演化分别呈现四重对称、双重对称和三重对称。基于晶体塑性理论,建立了各向异性蠕变构成模型和损伤模型,以反映取向引起的蠕变变形和损伤演化的差异。对第二代镍基单晶超合金整个蠕变过程的数值模拟表明,蠕变构效模型和损伤模型能够模拟不同取向下试样的变形和损伤,并可得到蠕变寿命。Journal of the Mechanics and Physics of SolidsSize effects in a power law creeping layer under compression or shear, and implications for deformation mechanisms of lithium filmsAlessandro Leronni, Vikram S. Deshpande, Norman A. Fleckdoi:10.1016/j.jmps.2023.105505压缩或剪切作用下幂律蠕变层的尺寸效应及其对锂膜变形机制的影响The axisymmetric compression of a power law creeping metallic sandwich layer of micron-scale thickness is analysed. Account is taken of the elevation in flow strength due to the presence of a spatial gradient in plastic strain rate. Numerical and analytical solutions reveal that the average compressive traction is enhanced by a combination of strain rate gradients and plastic constraint. A similar size effect is predicted for simple shear of the creeping sandwich layer. The difference in responses for compression and shear is traced to the different profiles of shear strain rate through the thickness of the layer. The sensitivity of compressive and shear strengths to the choice of higher-order boundary condition is explored, and good agreement with recent experiments on compression and shear of a thin sandwich layer of lithium is achieved by assuming fully clamped higher-order boundary conditions and a material length scale on the order of 3 − 5 μm in the strain gradient-based creep theory.对厚度为微米级的幂律蠕变金属夹层的轴对称压缩进行了分析。考虑到了塑性应变率的空间梯度导致的流动强度升高。数值和分析结果表明,平均压缩牵引力在应变率梯度和塑性约束的共同作用下得到增强。蠕变夹心层的简单剪切也会产生类似的尺寸效应。压缩和剪切响应的差异可追溯到通过层厚度的剪切应变率的不同剖面。研究还探讨了压缩和剪切强度对高阶边界条件选择的敏感性,并通过在基于应变梯度的蠕变理论中假设完全夹紧的高阶边界条件和 3 - 5 μm 量级的材料长度尺度,与最近的锂薄夹心层压缩和剪切实验取得了良好的一致性。International Journal of PlasticityNanoprecipitate and stacking fault-induced high strength and ductility in a multiscale heterostructured high-entropy alloyLiyuan Liu, Yang Zhang, Zhongwu Zhang, Junpeng Li, Weiguo Jiang, Lixin Sundoi:10.1016/j.ijplas.2023.103853多尺度异质结构高熵合金中的纳米沉淀和堆叠断层诱导的高强度和延展性Two-phase high-entropy alloys (HEAs) have high strength due to the contribution of interface-dependent strengthening, but the deformation incompatibility between the two phases causes instability. The initiation of cracks occurs at the two-phase interfaces, which ultimately leads to low ductility. To overcome this problem, the strategy proposed in this work is to introduce nanoprecipitates as a buffer zone and simultaneously promote stress release caused by the formation of stacking faults (SFs) at the two-phase interfaces, reducing the stress localization at the two-phase interface, thus improving the ductility. The Al16Cr20Fe10Co30Ni24 HEA was chosen as the model material to evaluate this approach. After rolling at 800°C, the HEA had a two-phase lamellar structure consisting of a face-centered cubic (FCC) phase and an ordered body-centered cubic BCC (B2) phase. Recrystallization occurred within the FCC phase, and precipitates were present in both the FCC and B2 lamellae. The B2 nanoprecipitates in the FCC phase play the most important role, contributing to the improvement of yield strength and buffering the direct contact between gliding dislocations and the two-phase interface. In addition, the B2 nanoprecipitates also promote the widespread formation of SFs at the two-phase interfaces, leading to stress release. More importantly, nanoprecipitates are nucleation sites for SFs. The formation of an SF network improves the strain-hardening ability. The HEA shows a yield strength of 1,120 MPa and an ultimate tensile strength of 1,540 MPa while still exhibiting an elongation to fracture of ∼25%.两相高熵合金(HEAs)由于界面强化作用而具有高强度,但两相之间的变形不相容性会导致不稳定性。裂纹在两相界面处产生,最终导致低延展性。为了克服这一问题,本研究提出的策略是引入纳米沉淀物作为缓冲区,同时促进两相界面上形成堆叠断层(SFs)引起的应力释放,减少两相界面上的应力局部化,从而提高延展性。我们选择 Al16Cr20Fe10Co30Ni24 HEA 作为模型材料来评估这种方法。在 800°C 下轧制后,HEA 具有两相薄片结构,包括面心立方(FCC)相和有序体心立方 BCC(B2)相。再结晶发生在 FCC 相中,FCC 和 B2 层状结构中都存在沉淀。FCC 相中的 B2 纳米析出物发挥了最重要的作用,有助于提高屈服强度,缓冲滑动位错与两相界面之间的直接接触。此外,B2 纳米沉淀物还能促进两相界面上 SFs 的广泛形成,从而导致应力释放。更重要的是,纳米沉淀物是 SF 的成核点。SF 网络的形成提高了应变硬化能力。HEA 的屈服强度为 1,120 兆帕,极限拉伸强度为 1,540 兆帕,而断裂伸长率仍为 25%。Thin-Walled StructuresKirigami-based inverse design for 3D surfaces formed by mechanically guided methodFuhua Ye, Jiaying Chang, Zhichao Fandoi:10.1016/j.tws.2023.111462基于折纸的反向设计,以机械引导法形成三维表面The mechanically guided assembly method utilizes the compressive buckling behavior of thin-film structures to transform two-dimensional (2D) precursors into three-dimensional (3D) structures. Previous research has shown that by inverse designing thickness and width distributions in 2D precursors, various 3D surfaces with target geometries can be accurately assembled. However, the variation in thickness poses significant challenges for the fabrication of the 2D precursor, especially on a small scale. In this paper, we propose a Kirigami-based inverse design framework that utilizes pre-specified incision patterns as critical parameters to control the bending stiffness distribution of 2D precursors. This enables the fabrication of target 3D structures with constant thickness, which greatly simplifies the production of 2D precursors. By studying the deformation characteristics of beam models during pure bending, we have established an analytical relationship between incision patterns and bending stiffness distribution. To validate the effectiveness of our inverse design theory, we conducted a series of simulations and experiments on 3D structures, yielding favorable comparison results. Moreover, guided by this inverse design theory, we have developed a microneedle structure through conceptual design, demonstrating the capability of Kirigami patterns in the inverse design of complex three-dimensional structures, and highlighting the potential application of our method in the biomedical field.机械引导装配法利用薄膜结构的压缩屈曲行为将二维(2D)前体转化为三维(3D)结构。以往的研究表明,通过对二维前驱体的厚度和宽度分布进行反向设计,可以精确装配出具有目标几何形状的各种三维表面。然而,厚度的变化给二维前驱体的制造,尤其是小规模制造带来了巨大挑战。在本文中,我们提出了一种基于桐花纹的逆向设计框架,利用预先指定的切口模式作为关键参数来控制二维前驱体的弯曲刚度分布。这样就能制造出厚度恒定的目标三维结构,从而大大简化了二维前驱体的生产。通过研究梁模型在纯弯曲过程中的变形特征,我们建立了切口模式与弯曲刚度分布之间的分析关系。为了验证逆向设计理论的有效性,我们在三维结构上进行了一系列模拟和实验,取得了良好的对比结果。此外,在这一逆向设计理论的指导下,我们通过概念设计开发了一种微针结构,证明了桐神图案在复杂三维结构逆向设计中的能力,并突出了我们的方法在生物医学领域的潜在应用。Frequency-constrained topology optimization in incompressible multi-material systems under design-dependent loadsThanh T. Banh, Soomi Shin, Joowon Kang, Dongkyu Leedoi:10.1016/j.tws.2023.111467设计相关载荷下不可压缩多材料系统中的频率约束拓扑优化In the realm of engineering design, structures grappling with fluidic pressure loads within precise frequency constraints necessitate innovative approaches. This study introduces a method to address the intricacies of design-dependent load-based structures, focusing on three key aspects: (i) managing structures constrained by frequency under fluidic pressure loads dependent on the design, (ii) integrating the use of multiple materials, and (iii) dealing with nearly incompressible materials. The proposed approach, detailed in this paper, employs polytopal composite finite elements (PCEs) to overcome the inherent volumetric locking phenomenon in incompressible materials. By incorporating Darcy’s law and a drainage term alongside the representative-solid phase, this approach ensures consistent treatment of fluidic pressure loads, dynamically adjusting their direction and location during the multi-material design process. The porosity of each element, intricately linked to its density variable through a Heaviside function, facilitates a smooth transition between solid and void phases. The application of Darcy’s law establishes a specific pressure field, solved using PCEs, enabling the computation of consistent nodal loads. This method simplifies the assessment of load sensitivities through the adjoint-variable technique. The method’s effectiveness and reliability are validated through numerical examples, demonstrating its capability to optimize compliance within specific volume constraints for frequency-limited structures subjected to design-dependent pressure loading and considering a diverse range of materials from compressible to nearly incompressible.在工程设计领域,要在精确的频率限制下解决流体压力负载问题,就必须采用创新方法。本研究介绍了一种方法来解决基于设计的复杂结构,重点关注三个关键方面:(i) 在流体压力载荷取决于设计的情况下管理受频率约束的结构;(ii) 综合使用多种材料;(iii) 处理几乎不可压缩的材料。本文详述的拟议方法采用了聚托帕尔复合有限元(PCE),以克服不可压缩材料固有的体积锁定现象。通过将达西定律和排水项与代表固体相结合,该方法可确保对流体压力负荷的一致处理,并在多材料设计过程中动态调整其方向和位置。通过海维塞德函数,每个元素的孔隙率都与其密度变量密切相关,从而促进了固相和空相之间的平稳过渡。达西定律的应用建立了一个特定的压力场,通过使用 PCEs 进行求解,可以计算出一致的节点荷载。这种方法通过邻接变量技术简化了对荷载敏感性的评估。该方法的有效性和可靠性通过数值示例得到了验证,证明了其在特定体积约束条件下优化频率受限结构的顺应性的能力,这些结构承受的压力荷载取决于设计,并考虑了从可压缩到几乎不可压缩的各种材料。Multi-patch isogeometric Kirchhoff–Love shell analysis for post-buckling of functionally graded graphene platelets reinforced composite shellsXiaoxiao Du, Ran Zhang, Wei Wang, Gang Zhao, Yazui Liudoi:10.1016/j.tws.2023.111470针对功能分级石墨烯平板增强复合材料壳体后屈曲的多斑块等几何基尔霍夫-洛夫壳分析This paper develops a multi-patch isogeometric Kirchhoff–Love shell method for post-buckling of functionally graded graphene platelets reinforced composite (FG-GPLRC) cylindrical, spherical, and conoidal shell structures, which are built with single or multiple NURBS patches. A penalty strategy is employed to weakly couple nonconforming interfaces between adjacent patches. The coupling work induced by enforcing displacement continuity and rotational continuity is added to the equilibrium equation, and the corresponding stiffness matrix is derived in detail. A simplified arc-length method is utilized to capture the complex equilibrium paths including snap-through and snap-back behaviors. Five distribution patterns of the shells including uniform (UD), V-type, A-type, O-type, and X-type are considered. The cylindrical and spherical shells are subjected to concentrated loadings at central points while for conoidal shells the concentrated loadings are enforced at the center points of an edge. The post-buckling of isotropic and laminated shell structures is first studied to validate the developed formulations by comparing the obtained results with those given in existing literature. Then a series of numerical examples considering nonlinear FG-GPLRC shell problems are conducted to explore the effect of various parameters like geometric dimensions, GPL distribution patterns, and shell thickness on the mechanical performance. Finally, the post-buckling of a cylindrical shell subjected to an offset concentrated load, with extremely complicated equilibrium paths, is modeled and analyzed by using the developed multi-patch isogeometric method. The numerical results reveal that the X-type GPL distribution pattern demonstrates better performance in load–deflection responses and provides the largest buckling critical load among the five patterns. Additionally, the increase in height ratio could deteriorate the stability performance of FG-GPLRC conoidal shells.本文针对功能分级石墨烯平板增强复合材料(FG-GPLRC)圆柱形、球形和圆锥形壳体结构的后屈曲问题,开发了一种多补丁等几何基尔霍夫-洛夫壳体方法,该方法由单个或多个 NURBS 补丁构成。采用惩罚策略对相邻贴片之间的不符合界面进行弱耦合。通过强制位移连续性和旋转连续性引起的耦合功被添加到平衡方程中,并详细推导出相应的刚度矩阵。利用简化弧长法捕捉复杂的平衡路径,包括快穿和快退行为。考虑了五种壳体分布模式,包括均匀(UD)、V 型、A 型、O 型和 X 型。圆柱形和球形壳体在中心点承受集中载荷,而圆锥形壳体则在边缘中心点承受集中载荷。首先研究了各向同性和层状壳体结构的后屈曲,通过比较所获得的结果和现有文献中给出的结果来验证所开发的公式。然后,通过一系列考虑非线性 FG-GPLRC 壳体问题的数值示例,探讨了几何尺寸、GPL 分布模式和壳体厚度等各种参数对力学性能的影响。最后,使用所开发的多补丁等几何方法对承受偏移集中载荷的圆柱形壳体的后屈曲进行了建模和分析,该壳体的平衡路径极其复杂。数值结果表明,X 型 GPL 分布模式在载荷-挠度响应方面表现更佳,在五种模式中提供了最大的屈曲临界载荷。此外,随着高度比的增加,FG-GPLRC 圆锥壳的稳定性能也会下降。来源:复合材料力学仿真Composites FEM

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